Roofing plate with eave-sided plastic strip

ABSTRACT

The invention relates to a roofing plate produced as an injection-moulded plastic piece, supporting a functional unit for fitting to the roof surface such as a roof ventilator, extended on the edge thereof with a predominantly plastically deformable strip, made from lead sheet for example, which extends into a groove in the boundary region of the injection-moulded plastic piece and is retained there with a positive fit against outward movement. The strip is exclusively arranged on the eave-sided edge of the roofing plate and the groove around the boundary region of the strip on the roof plate has groove edges inclined towards the groove opening in cross-sectional view.

The invention relates to a roofing plate which is produced as a plastic injection molding and carries a functional unit to be arranged in the roof surface, such as, for example, a ventilation device which is fastened to the roof surface and projects upward above the latter.

Since the part of roof ventilators which inevitably projects above the roof surface should be disposed perpendicularly irrespective of the inclination of the roof surface for visual reasons, roof ventilators are often designed to be adjustable in inclination. In a widespread type of construction, a tube penetrates the roof plane from below and opens into a dome arching upward from the penetrated roofing plate. The dome surface is perforated and covered by a hood surface, which opens upward into an outlet tube. The hood surface and with it the outlet tube are pivotable on the dome about an axis lying horizontally normal to the line of slope of the roof, whereby the outlet tube can be set perpendicularly irrespective of the inclination of the roof surface.

Roof ventilators of this type are produced from plastic injection moldings. A typical example is described in AT 412 793. Thus one type of roof ventilator is certainly sufficient for all inclinations of roofs which are covered with a certain type of roofing tile, but a separate embodiment variant is required virtually for every type of roofing tile appearing on the market, the roofing plate form of which is adapted in its marginal region to the respective type of roofing tile. Thus the number of parts which is produced per injection mold becomes relatively small, the tool cost share of the cost of the parts becomes relatively high. There is also considerably outlay for delivery, stock-keeping and timely correct selection of the individual variants.

For this reason, it is attempted to make the regions of the roof ventilator that are to be adapted individually to specific types of roofing tiles from plastically deformable material, typically from lead sheet. DE 92 00 759 U1 describes a roof leadthrough in dome/hood type of construction. The roofing plate in this case is formed from a readily plastically deformable metal sheet, typically from lead; the dome is designed as a plastic injection molding. At the connecting line between dome and roofing plate, the sheet part is provided with a groove, the base of which is perforated by holes. The sheet region with the groove is encapsulated on both sides with the plastic of the dome in the injection mold. A disadvantage with this type of construction is that a relatively high degree of scrap occurs on the valuable metal sheet and that the device does not withstand the environmental conditions at the roof very well in relative terms, with the considerable fluctuations in temperature and wetness.

DE 295 20 505 U1 proposes a type of construction for a roof leadthrough in dome/hood type of construction which differs from the type of construction described above in that a permanently elastic layer is embedded in the overlapping region between metal sheet and plastic, said layer causing the components used to bear tightly against one another for a long time and thus preventing the penetration of moisture, causing destruction, into the contact surface. According to this type of construction, the outlay is again increased. Unfortunately the effect of the elastic layer in accordance with the intended use is lost in too short a time.

DE 29721602 U1 likewise describes a combination of a plastic dome with a roofing plate of lead sheet. The dome-side margin of the lead sheet is in this case clamped in place between the foot region of the dome on the top side and a plastic ring on the underside, which are anchored to one another. It proves to be difficult to dimension the components in such a way that, on the one hand, they are retained permanently on one another and also provide a seal in use under the difficult environmental conditions and, on the other hand, can nonetheless be mounted on one another without any problems.

EP 949392 A2 shows a roof decking plate, e.g. for the installation of a ventilator, which is provided at its margin on the eave side with a groove which widens inward from the outer margin of the cross-sectional area and in which a sealing strip in the form of an apron provided with a marginal bead is detachably fastened. This apron may be formed, for example, from a lead sheet. A disadvantage with this type of construction is that it is not possible to produce this groove in a plastic injection molding at a reasonable cost and that the fitting of the apron at this groove requires a separate operation.

It is relatively simple to readily seal the roofing plate, which is relatively thin compared with roofing tiles, of a roof ventilator at its lateral margins and at its top margin in combination with the adjoining roofing tiles of an inclined roof without the roofing plate for this purpose being adapted precisely to the individual type of roofing tile. This is only difficult at the bottom margin, on the eave side, of the roofing plate. Taking this fact into account, roof leadthroughs in dome/hood type of construction in which the roofing plate is injected in one piece with the dome are obtainable on the market, a flexible sealing strip of corrugated non-rigid PVC being integrally formed on the margin of the roofing plate on the eave side, the profile direction of the corrugations running along the line of slope of the roof. An embodiment variant of this type of construction is suitable for combination with many different embodiment variants of roofing tiles. The above-described problems at the metal/plastic transition are avoided through the use of a plastic material as sealing strip. A disadvantage with this type of construction is that the sealing strip cannot actually be adapted to the geometry of the roofing tile following on the eave side, since the range of its elastic deformability in relation to the range of its plastic deformability is too high. In practical terms this means that the sealing strip stands out in a plurality of large corrugations from the roofing tile against which it should actually bear.

Proceeding from this prior art, the object of the invention is to provide a roof ventilator produced as a plastic injection molding for inclined roof surfaces, it being possible to combine the roofing plate of said roof ventilator with various types of adjoining roofing tiles. The roofing plate is to reliably perform its sealing task with long-lasting effect in this combination, and the entire arrangement is to be capable of being produced at a lower cost compared with previously known embodiments.

According to claim 1, the object is achieved by the roofing plate of the roof ventilator being produced as a plastic injection molding which is provided only at the margin on the eave side with a strip made of a corrugated, readily plastically deformable and not very elastically deformable and sufficiently chemically resistant material, this strip, in its marginal region connected to the plastic, projecting into a groove open downward in the plastic and being held in this groove in a positive-locking manner against movement outward. Lead is very suitable as material for the corrugated strip, but alloys of other metals, such as copper alloys for example, are also conceivable. Composites of a plurality of materials, for example those which are composed of metal layers and plastic layers, also appear to be readily suitable, since plasticity and good connecting properties can thus be achieved. Provided plastics are obtainable which have appropriate deformation and resistance properties on their own, said plastics can of course also be readily applied for this purpose.

The invention will become clearer with reference to the drawings:

FIG. 1 shows a roofing plate according to the invention together with strip in a perspective view.

FIG. 2 shows the relevant part of the embodiment in FIG. 1 in a lateral side view.

Owing to the fact that the strip 2 of plastically deformable planar material is arranged only at the margin of the roofing plate 1 on the eave side, the groove 1.1 into which it projects on the roofing plate 1 can easily be formed with flanks directed downward toward the opening. As a result, leakage problems do not occur even if the strip 2 and the plastic of the roofing plate 1 no longer bear fully against one another at sometime or other, but rather a gap forms between them. So that the strip 2 and the roofing plate 1 do not become detached from one another in the process, the strip 2, in the present example, is provided with apertures 2.1.1 in the marginal region 2.1 encapsulated by the plastic, into which apertures 2.1.1 the plastic of the roofing plate 1 penetrates during the injection molding operation. As a result, the strip 2 is held in a positive-locking manner to prevent it from being pulled out of the groove 1.1. In order to be able to comfortably avoid leakage problems between the roofing plate 1 and the adjoining roofing tiles on the eave side by appropriately placing the plastically deformable strip 2 during fitting on the roof, it is advisable to allow the strip 2 to project beyond the side edges of the roofing plate 1. For the same reason, the strip 2 should be of corrugated design in the region of its width remote from the roofing plate 1, in which case the profile direction of the corrugations 2.2 is ideally to be oriented normal to the connecting line with the roofing plate 1, that is to say parallel to the line of slope of the roof surface. In the region of the corrugations 2.2, the enveloping surface of the strip is not only bendable but also extensible normal to the profile direction of the corrugations 2.2 without large expenditure of force.

During the production of the composite part consisting of roofing plate 1 and strip 2, the marginal region 2.1, provided with apertures 2.1.1, of the strip 2 is encapsulated with the plastic forming the roofing plate 1 in a mold consisting of halves pressed against one another and enclosing a cavity. To this end, the strip must be firmly clamped in place in a precisely defined position between parts of the injection mold. It is advantageous in this case to put a correspondingly cut-to-size and drilled, flat strip made of the plastically deformable material into the injection mold and to form the corrugations 2.2 by the pressure of the mold halves against one another, which is required in any case. To this end, the mold halves must of course be provided with the corresponding negative surface contour.

The invention has been explained with reference to application for ventilation devices. However, it is in principle suitable for all applications in which it is appropriate for parts which have to be installed in a roof surface to be held by a roofing plate designed as a plastic injection molding. Applications which may be mentioned are, for example, skylights, dormers, chimney flashings, wall connections. 

1. A roofing plate produced as a plastic injection molding for inclined roof surfaces, said roofing plate carrying a functional unit to be arranged in the roof surface and being widened at its margin with a predominantly plastically deformable strip which in contrast is scarcely elastically deformable or is not elastically deformable at all and is made of a planar material and which projects into a groove in the marginal region of the plastic injection molding and is held in a positive-locking manner therein against movement outward, characterized in that only that margin of the roofing plate which is on the eave side is provided in this way with a strip of predominantly plastically deformable planar material, and in that the groove enclosing the marginal region of the strip on the roofing plate is formed, in cross-sectional view, with groove flanks inclined downward toward the groove opening.
 2. The roofing plate as claimed in claim 1, characterized in that that marginal region of the strip which projects into the groove in that marginal region of the roofing plate which is on the eave side is perforated by apertures, and in that the plastic material of the roofing plate projects into these apertures.
 3. The device as claimed in claim 1, characterized in that the strip projects in its longitudinal direction on both sides beyond the width of the roofing plate.
 4. The device as claimed in claim 1, characterized in that the strip is designed with corrugations in its marginal region remote from the roofing plate.
 5. A method of producing a device as claimed in claim 4, characterized in that, as initial material for the strip, a flat strip of planar plastic material is inserted between the mold halves of the injection mold enclosing the mold cavity for the roofing plate, and in that the corrugations are embossed in the strip by the mold halves of the injection mold.
 6. The device as claimed in claim 1, characterized in that the strip is formed from a lead or copper alloy.
 7. The device as claimed in claim 1, characterized in that the strip is formed by a composite of metal and plastic. 